Yes, the searching can be tedious, especially when you attempt to include a scale (1/72, 1:72, etc.). You pretty much just have to get close to what you want, sit back, and scroll for a while. Make sure to set up a collection or two so you can save interesting things you come across, making it easier to get back to them later.
Regarding scale, don't let that hold you up too much. Most (all?) slicers will allow you to re-scale whatever STL file you download. If the maker was kind enough to include the source scale, you can simply use the formula (source scale / target scale) x 100 to get to the factor you need. If they did not include a scale, all you can do generally is print it as-is, get out your measuring tools, and figure out what you need to change. I had one a while ago that was sized to fit the build plate (a cousin to "box scale" models, I guess), so I printed it, measured the wingspan, compared that to the 1:1 data, and came up with the correct reduction factors.
To the other sites others have mentioned, you can add Printables.com.
Good luck!
Jim
(Anycubic Photon Mono X)
(Prusa i3 Mk3S+)
(Bambu Labs X1 Carbon)